The present invention relates to the use of 4-chloro-5-(4,5-dihydro1H-imidazol-2-yl)-amino!-6-methoxy-2-methyl-pyrimi dine (=moxonidine) and the physiologically compatible acid addition salts thereof for the treatment and/or prophylaxis of renal failure in normotensive patients; to the preparation of medicaments suitable for this treatment, and to pharmaceutical compositions for effecting such a treatment.